SAR determination and influence of the human head in the radiation of a mobile antenna for two different frequencies

The big proliferation of mobile communication systems has caused an increased concern about the interaction between the human body and the antennas of mobile handsets. In order to study the problem, a multiband antenna was designed, fabricated and measured to operate over two frequency sub bands 900 and 1800 MHz. After that, we simulated the same antenna, but now, in the presence of a human head model to analyze the head's influence. First, the influence of the human head on the radiation efficiency of the antenna has been investigated as a function of the distance between the head and the antenna and with the inclination of the antenna. Furthermore, the relative amount of the electromagnetic power absorbed in the head has been obtained.

Renormalization-group constraints on Yukawa alignment in multi-Higgs-doublet models

We write down the renormalization-group equations for the Yukawa-coupling matrices in a general multi-Higgs-doublet model. We then assume that the matrices of the Yukawa couplings of the various Higgs doublets to right-handed fermions of fixed quantum numbers are all proportional to each other. We demonstrate that, in the case of the two-Higgs-doublet model, this proportionality is preserved by the renormalization-group running only in the cases of the standard type-I, II, X, and Y models. We furthermore show that a similar result holds even when there are more than two Higgs doublets: the Yukawa-coupling matrices to fermions of a given electric charge remain proportional under the renormalization-group running if and only if there is a basis for the Higgs doublets in which all the fermions of a given electric charge couple to only one Higgs doublet.

Influence of the Human Head in the Radiation of a Mobile Antenna

The big proliferation of mobile communication systems has caused an increased concern about the interaction between the human body and the antennas of mobile handsets. In order to study the problem, a multiband antenna was designed, fabricated and measured to operate over two frequency sub bands 900 and 1800 MHz. After that, we simulated the same antenna, but now, in the presence of a human head model to analyze the head's influence. First, the influence of the human head on the radiation efficiency of the antenna has been investigated as a function of the distance between the head and the antenna and with the inclination of the antenna. Furthermore, the relative amount of the electromagnetic power absorbed in the head has been obtained. In this study the electromagnetic analysis has been performed via FDTD (Finite Difference Time Domain).

Assessment of fungal contamination in a group of Lisbon's gymnasiums with a swimming pool

The study’s main purpose was the assessment of the environmental fungal contamination, the exploration of possible associations between related environmental variables and the study of the relationship between fungal contamination of air and surfaces. A descriptive study was developed based upon air and surfaces monitoring for fungal contamination in ten indoor gymnasiums with a swimming pool located in Lisbon’s urban area. Fifty 200 litres air samples and 120 surface swabs were collected. Surfaces samples were collected before and after cleaning and disinfection and temperature and relative humidity values were registered during the collection period. Twenty five different species of fungi were identified in the air samples, being the three most commonly isolated genera the following: Cladosporium (36.6%), Penicillium (19.0%) and Aspergillus (10.2%). Thirty-seven different species of fungi were identified in the surface samples. Fusarium sp. was the most frequent genera before (19.1%) and after (17.2%) cleaning and disinfection. There was a significant association between the numbers of visitors and the fungal contamination determined in the surface samples (p<0.05). There was no significant association (p>0.05) between the contamination encountered in the air samples and the one registered in the surface samples and between the fungal contamination and the temperature or relative humidity measured on location. The data obtained enabled the assessment of the establishment’s fungal contamination and led the authors to conclude, consequently, that physical activity, which generally promotes health, can in fact be challenged by this factor.

Cognitive deficit and depressive symptoms in a community group of elderly people: a preliminary study

Since the number and proportion of old people increases worldwide, health professionals and systems should be made aware and prepared to deal with their problems. Cognitive deficit and symptoms of depression are commom among the elderly, and may occur in relation to various risk factors such as health conditions and psychosocial variables. In order to study cognitive deficit and the presence of signs and symptoms of depression, 62 elderly community subjects enrolled at a Community Health Unit in Porto Alegre, southern Brazil, were interviewed. They were evaluated by means of the Mini Mental State Exam, the Montgomery-Asberg Depression rating scale, and a questionnaire on health conditions, living arrangements and social variables. Higher levels of symptoms of depression were observed among subjects exposed to major risk factors for cerebrovascular diseases (diabetes and coronary disease), while impaired cognitive performance was seen among individuals who could not count on the presence of a confidant (social network variable). The results suggest that the early identification of major risk groups among old people can help to prevent institutionalization and keep individuals in the community.

From efficiency to optimality in proportional reinsurance under group correlation

Based on our recent discovery of closed form formulae of efficient Mean Variance retentions in variable quota-share proportional reinsurance under group correlation, we analyzed the influence of different combination of correlation and safety loading levels on the efficient frontier, both in a single period stylized problem and in a multiperiod one.

Virtual communities of practice: investigating motivations and constraints in the processes of knowledge creation and transfer

With accelerated market volatility, faster response times and increased globalization, business environments are going through a major transformation and firms have intensified their search for strategies which can give them competitive advantage. This requires that companies continuously innovate, to think of new ideas that can be transformed or implemented as products, processes or services, generating value for the firm. Innovative solutions and processes are usually developed by a group of people, working together. A grouping of people that share and create new knowledge can be considered as a Community of Practice (CoP). CoP’s are places which provide a sound basis for organizational learning and encourage knowledge creation and acquisition. Virtual Communities of Practice (VCoP's) can perform a central role in promoting communication and collaboration between members who are dispersed in both time and space. Nevertheless, it is known that not all CoP's and VCoP's share the same levels of performance or produce the same results. This means that there are factors that enable or constrain the process of knowledge creation. With this in mind, we developed a case study in order to identify both the motivations and the constraints that members of an organization experience when taking part in the knowledge creating processes of VCoP's. Results show that organizational culture and professional and personal development play an important role in these processes. No interviewee referred to direct financial rewards as a motivation factor for participation in VCoPs. Most identified the difficulty in aligning objectives established by the management with justification for the time spent in the VCoP. The interviewees also said that technology is not a constraint.

Children visual screening protocol: validation by a focus group panel of experts

Screening programs, particularly the inclusion of specific orthoptic tests to detect visual abnormalities, varies among countries. This study aims to: 1) describes expert perception of issues related with children visual screening; 2) identify specific orthoptic tests to detect visual abnormalities in children visual screening.

Mobile Banking: fatores determinantes na adesão

Dissertação apresentada à Escola Superior de Comunicação Social para obtenção de grau de mestre em Publicidade e Marketing.

Reconfigurable antenna for mobile devices

O trabalho descrito nesta dissertação de mestrado foca-se em geral na investigação de antenas impressas. São apresentados conceitos básicos, em conjunto com alguns exemplos desenvolvidos. No entanto, o principal foco prende-se com técnicas de miniaturização e reconfigurabilidade de antenas. A miniaturização de antenas é um tema de investigação de longa data, no entanto, novas técnicas e soluções são apresentadas regularmente. Nesta tese, é aplicada uma técnica recente, baseada na introdução de indutores encapsulados no elemento ressonante de uma antena, que permite miniaturizar um monopólio impresso com uma frequência de ressonância de 2.5 GHz. Outro assunto abordado neste trabalho é a reconfigurabilidade de antenas. Algumas das técnicas mais comuns na investigação actual são apresentadas e debatidas. Uma solução com recurso a díodos PIN é usada para estudar esta capacidade. Os conceitos e características deste tipo de componentes são apresentadas sendo feito o desenho e fabrico de um possível monopólio impresso reconfigurável para operação em dupla banda. Por fim, são combinadas as técnicas de miniaturização com inductor encapsulado e reconfigurabilidade através de díodos PIN, por forma a projectar uma antena reconfigurável muito pequena, para operação em duas bandas distintas. Os resultados são discutidos e com base nestes, algumas possíveis otimizações são propostas. The work reported in this dissertation is focused in the printed antenna research. Basic concepts of printed antennas are presented, along with a few examples that were developed. The main focus however, is around miniaturization and reconfigurability of antennas. Antenna miniaturization is a long time research subject, however, new techniques and solutions are presented everyday. In this thesis, a recent technique based on the introduction of chip inductors in the resonating element of a printed antenna is used in order to miniaturize a monopole with a resonating frequency at 2.5 GHz. Another issue approached in this work is antenna reconfigurability. Some common techniques used in antenna reconfiguration are presented and debated. A solution with PIN diodes is used to study this capability. The concepts and characteristics of this type of components are presented and an example of a reconfigurable printed monopole for dual-band operation is designed and fabricated. At last, miniaturization with chip inductor and reconfigurability through PIN diodes are used together to create a very small antenna for dual-band operation. The simulated and measured results are discussed and upon these, some possible optimizations are proposed.

Comparative analysis of the ground reaction forces, during the support phase, in a group of pregnant women on their 3rd trimester of pregnancy and in a group of not pregnant women

PURPOSE: To analyze and compare the Ground Reaction Forces (GRF), during the stance phase of walking in pregnant women in the 3rd trimester of pregnancy, and non pregnant women. METHODS: 20 women, 10 pregnant and 10 non pregnant, voluntarily took part in this study. GRF were measured (1000 Hz) using a force platform (BERTEC 4060-15), an amplifier (BERTEC AM 6300) and an analogical-digital converter of 16 Bits (Biopac). RESULTS: The study showed that there were significant differences among the two groups concerning absolute values of time of the stance phase. In what concerns to the normalized values the most significant differences were verified in the maximums values of vertical force (Fz3, Fz1) and in the impulse of the antero-posterior force (Fy2), taxes of growth of the vertical force, and in the period of time for the antero-posterior force (Fy) be null. CONCLUSIONS: It is easier for the pregnant to continue forward movement (push-off phase). O smaller growth rates in what concerns to the maximum of the vertical force (Fz1) for the pregnant, can be associated with a slower speed of gait, as an adaptation strategy to maintain the balance, to compensate the alterations in the position of her center of gravity due to the load increase. The data related to the antero-posterior component of the force (Fy), shows that there is a significant difference between the pregnant woman’s left foot and right foot, which accuses a different functional behavior in each one of the feet, during the propulsion phase (TS).

Personalized sightseeing tours support using mobile devices

In this paper, we present PSiS (Personalized Sightseeing Tours Recommendation System) Mobile. PSiS Mobile is our proposal to a mobile recommendation and planning support system, which is designed to provide effective support during the tourist visit with context-aware information and recommendations about places of interest (POI), exploiting tourist preferences and context.

Perspetivas das educadoras de infância de uma instituição particular de solidariedade social sobre o contributo da colaboração para o seu desenvolvimento profissional

Dissertação apresentada à Escola Superior de Educação de Lisboa para obtenção de grau de mestre em Ciências da Educação, especialidade em Supervisão em Educação

Perspetivas dos professores do 1º ciclo sobre a supervisão no processo de avaliação de desempenho e os seus efeitos no desenvolvimento profissional

Dissertação apresentada à Escola Superior de Educação de Lisboa para obtenção de grau de mestre em Ciências da Educação, especialização Supervisão em Educação

Tourism mobile and recommendation systems - a state of the art

Recommendation systems have been growing in number for the last fifteen years. To evolve and adapt to the demands of the actual society, many paradigms emerged giving birth to even more paradigms and hybrid approaches. Mobile devices have also been under an incredible growth rate in every business area, and there are already lots of mobile based systems to assist tourists. This explosive growth gave birth to different mobile applications, each having their own advantages and disadvantages. Since recommendation and mobile systems might as well be integrated, this work intends to present the current state of the art in tourism mobile and recommendation systems, as well as to state their advantages and disadvantages.